Photo by Grant MacHamer
If you've ever walked through downtown SF, especially along Market Street, you may have noticed clouds of steam rising from various vents and manholes. It turns out that this mysterious steam comes from a network of pipes has been heating up downtown SF for nearly a century.
Over 180 customersincluding SF City Hall, the Moscone Convention Center and the Golden Gate TheaterUse steam for space heating, water heating, air conditioning and other purposes.
Two huge cauldrons, located in SoMA And Lower Nob Hilllet the steam through 13 miles of underground pipes which form the steam cycle in the city center. This system is responsible for overheating 37 million square meters of commercial, residential and government buildings.
The company that operates this steam network, Cordia, serves a 2 square mile area in SF's central business district.
Courtesy of Cordia
Both steam generation plants use boilers heated by natural gas. The plant's combined heat and power (CHP) system generates 500 kW of electricity, This makes the system essentially energy self-sufficientsaid Cordia.
Critics of the system point out that the system also produces heat Almost a waste 250,000 gallons of water per dayaccording to a 2015 CBS Bay Area story.
Cordia addressed this problem by engaging in a water reclamation project Pump 30 million gallons of groundwater per year beneath Powell Street Station. The groundwater is purified and used in the boilers, reducing the need for municipal drinking water.
Not every drop of water in the steam circuit is wasted. Some of Cordia's 180 customers use some of the wastewater from their steam lines Landscaping and toilet flushingwhich includes SF City Hall.
